去除重金属的工程菌对小鼠的毒性

Toxicity of a Heavy Metal Removal Engineering Strain to Mice

目的研究去除重金属的工程菌R32被排放到环境中后对小鼠的毒性。方法采用4种受试物(处理液1:分别含1、2、5、10g/L纯培养的R32菌体;处理液2:取处理20mg/L铬液2h的R32按处理液1方法配制;处理液3:含50g纯培养的R32菌体在1、3、5和7d内的分泌物溶液;处理液4:取处理20mg/L铬液2h的R32按处理液3方法配制)分别对昆明种小鼠进行急、慢性毒性实验,蓄积毒性实验,小鼠骨髓嗜多染红细胞微核试验和小鼠精子畸变试验,观察吸附重金属铬前后的工程菌R32及其分泌物对小鼠的毒性。结果急性毒性实验的各实验组的小鼠全部存活,进食增加且精神状态和生长发育良好,活动、排便、外观均未见异常。慢性毒性实验的各实验组的小鼠全部存活,进食量有不同程度增加,精神状态良好,活动和反应能力无异常。给予处理液1、3、4的各实验组小鼠未见中毒症状,全部存活,而给予处理液2的各实验组小鼠在染毒12d后开始出现进食量减少,体重增长减缓;14d后部分小鼠体重开始降低;19d后开始出现2只死亡雌性小鼠。给予处理液1、3、4的各实验组小鼠骨髓嗜多染红细胞微核率与阴性对照组差异无统计学意义(P>0.05),可见熏未吸附铬的R32及其吸附铬前后的分泌物均不会引起小鼠骨髓嗜多染红细胞微核发生率升高。给予处理液2的各实验组小鼠中,1、2、5mg/L投菌量的实验组与阴性对照组相比,微核率差异无统计学意义(P>0.05);10mg/L投菌量的实验组微核率高于对照组且有统计学意义(P<0.01)。给予处理液1、2、3、4的各实验组精子畸变率与阴性对照相比,差异均无统计学意义(P>0.05)。结论吸附铬前的R32及其在吸附前后所分泌的分泌物对小鼠均无急性毒性、慢性毒性和蓄积毒性;吸附铬后的R32对小鼠的急性毒性、慢性毒性以及精子畸变的影响不明显,但有一定的蓄积毒性,对小鼠的微核率也有一定的影响。

Objective To test the toxicity of genetically engineered strain R32 released to the environment. Methods Acute,chronic and cumulative toxicity test on mice,micronucleus assay of mice bone marrow cell and mice sperm malformation test were conducted to assess the toxicity of strain R32. Results R32 did not cause acute,chronic, cumulative and genetical toxic effect on mice before it absorbed heavy metal chromium. Although the mice bone marrow micronucleus frequency increased and some cumulative toxic effect emerged after R32 absorbed chromium,it did not cause acute and chronic toxicity effect on mice and mice sperm malformation rate did not increase neither. Furthermore, whether R32 absorbed heavy metal chromium or not, the effect of its secretion was not significant in all experiments compared with the control. Conclusion R32 can not cause toxic effect on mice before it absorbed chromium. Whether R32 absorbed chromium or not,the effect of its secretion was not significant in all toxicological experiments conducted in the present paper. Large content of R32 may cause some cumulative toxic effect in mice after it absorbed chromium.